[DSTAR_DIGITAL] Legally Identifying?

[Chip]

With D-STAR, is it necessary to verbally identify transmissions with your 
callsign? My question assumes that the MYCALL field is correctly set of course. 
A local friend and I have frequent simplex conversations and have been saying 
our callsigns to be safe, but since the radio is encoding our calls, is it 
actually necessary?
-Chip Legett, WX9EMT